If you aren’t eating less meat to reduce your carbon footprint, you might consider doing it just for your health. A large study found that eating a plant-based diet packed with vegetables, whole grains, nuts and legumes can reduce the risk of bowel cancer in men by over a fifth – in line with previous studies pointing in the same direction.
Bowel cancer is the third most common cancer worldwide, and while screening and treatment have improved, preventive strategies to lower the risk remain a priority. Diet is an important modifiable risk factor. Red and processed meats are linked with a higher risk of cancer, while foods rich in fiber are associated with a decreased risk. But the specifics of how individual cancers are affected by diet patterns are still poorly understood.
This is where the new study comes in.
The study, involving almost 80,000 men and over 93,000 women, found that men who ate the largest amounts of healthy plant-based foods had a 22% lower risk of bowel cancer compared to those who ate the least. No such link was found in women, which the researchers explained by women being less at risk for this type of cancer.
“In our study population, women consumed greater amounts of healthy plant foods and fewer amounts of unhealthy plant foods compared to men, and they might not have further benefits with higher scores of plant-based diet indices. In addition, men are at higher risk for colorectal cancer than women in general,” the researchers wrote in their paper.
Diets and healthy habits
For the study, participants were asked about the frequency with which they ate certain foods and drinks out of a list of 180 items. They were also asked about the size of the portions. They could say they consumed each food item “never or hardly ever” up to “two or more times a day,” while for drinks options reached up to “four or more times a day.”
The food and drink items in the list were classified into three groups, based on how “good” they are: healthy plant foods (vegetables, whole grains, nuts, legumes such as lentils, tea, and coffee), less healthy plant foods (refined grains, fruit juices, potatoes, and added sugars) and animal foods (dairy, eggs, animal fat, fish or seafood, and meat)
The researchers believe the antioxidant and anti-inflammatory features of fruits, vegetables, and whole grains in a plant-based diet could be the reason behind the lower cancer risk. Dietary fiber leads to the production of fatty acids through microbial fermentation, which reduces inflammation and carcinogenesis, they explained, while meat can have exactly the opposite effect.
“Although previous research has suggested that plant-based diets may play a role in preventing colorectal cancer, the impact of plant foods’ nutritional quality on this association has been unclear,” Jihye Kim, corresponding author, said in a statement. “Our findings suggest eating a healthy plant-based diet is linked with a reduced risk of colorectal cancer.”
The researchers cautioned that this is still an observational study that established a correlation, and there’s no clear causation demonstrated between the link between plant-based food and bowel cancer. The researchers call for more research to be done in the same field, hoping to better understand the role of diets in the fight against cancer.